Generally, hard tungsten carbide (WC) scraps such as chips, wires, bolts, drills, etc., that are metalworking tools to be discarded after being used, contain about 70 to 92 wt % of tungsten, and about 3 to 25 wt % of high-priced metals such as cobalt used as a binder of tungsten carbide (WC) powder, etc., wherein amounts of the tungsten, cobalt, etc., may vary depending on kinds, production year, and forms of the hard tungsten carbide (WC) scrap. However, since it is difficult to perform crushing and leaching, recycling the tungsten and the cobalt raw materials from the hard tungsten carbide (WC) scraps has not been achieved.
The tungsten and the cobalt contained in waste of the hard tungsten carbide (WC) scraps such as chips, wires, bolts, drills, etc., that are metalworking tools to be discarded after being used, occupy a significantly important position as raw materials in high-tech industries such as tool steel, and are high value-added materials as high-priced resources, and accordingly, it is unfortunate to treat the tungsten and the cobalt as waste.
Accordingly, under a domestic situation in which a total amount of the tungsten and the cobalt depends on imports as a resource poor country, when the tungsten, the cobalt, etc., are recovered and recycled from the hard tungsten carbide (WC) scraps in view of recycling of resources, it is economically helpful for the countries and is effectively useful as a resource.
A process for recovering the tungsten and the cobalt from the hard tungsten carbide (WC) scraps such as chips, wires, bolts, drills, etc., that are metalworking tools to be discarded after being used essentially includes a process of crushing the tungsten carbide (WC) scraps and preparing the tungsten carbide (WC) scraps into powder in order to effectively recover the tungsten and the cobalt.
When the process for crushing the hard tungsten carbide (WC) scraps is a simple crushing process, it has problems in that a long period of time is required, energy is largely consumed, and a crusher to be used has problems in view of durability, and noise pollution is severe.
In order to solve these problems, Korean Patent Registration No. 10-1226614 suggests a method for separating and crushing tungsten and cobalt from hard tungsten carbide (WC) scraps by using zinc. However, this method has problems in that a repeat process of removing zinc used for separating and crushing the tungsten and the cobalt through volatilization requires a long period of time, energy is largely consumed, and it is not easy to achieve a processing condition in which zinc evaporation needs to be inhibited by minimizing oxygen during the process.
In addition, Korean Patent Registration No. 10-1431706 suggests a method for oxidizing hard tungsten carbide (WC) scraps under a high concentration of oxygen atmosphere and then crushing the oxidized hard tungsten carbide (WC) scraps. However, this method has problems in that a reaction rate at which the hard tungsten carbide (WC) scraps are oxidized by high concentration of oxygen is slow, such that a long period of processing time and a repeated oxidation process are required.
Therefore, the present disclosure provides a method for crushing hard tungsten carbide scraps including forming the tungsten and the cobalt contained in the hard tungsten carbide (WC) scraps into an intermetallic compound, and oxides in a sponge form by using aluminum, followed by crushing, and a method for recovering the tungsten and the cobalt from the crushed hard tungsten carbide (WC) scrap powder.